P, Q R are the points so that PR = 3 cm, QR = 5 cm and PQ = 8 cm. The number of circle passing through the points P, Q, R is
3
2
1
1
The average age of 3 friends is 23. Even if the age of 4th friend is added, the average age remains the same. Then the age of the four friend is
20 years
21 years
22 years
22 years
If , then the value of
is
0
0
C.
0
If then
Length of a chord PQ of a circle with centre O is 4 cm. If the distance of PQ from the point O is 2 cm, then the length of the diameter is
2√2
3√2
5√2
4√2
The shadow of a vertical tower on ground level increases by 10 m when the altitude of the sun changes from 45° to 30°. The height of the tower is
5( √3 + 1 ) m
10( √3 - 1 ) m
9 m
13 m
An arc AB of a circle subtends an angle x radius at the centre of the circle. Given that the area of the sector AOB is equal to the square of the length of the arc AB, then the value of x is
1/√2
1/2
1/√3
1/3